Fountain pen



pril 11, 1939. A. H. s'n-:NERSEN FOUNTAIN PEN Original Filed June 3,1935 faz/erw: 1 ZZberZ He/efen,

Patented Apr. 11, 1939 UNITED STATES PATENT omer Application June 3,1935,

Serial No. 24,663

Renewed September 12, 1938 8 Claims.

This invention relates to fountain pens and pertains particularly toself-filling fountain pens of the piston type, i. e., the type having apiston operable in the pen barrel to elfect the filling of the inkreservoir.

One of the objects of the invention is the provision of an improvedconstruction for a fountain pen of the piston type which will facilitatethe feeding of ink from the ink reservoir to the pen point so as to keepthe pen point constantly supplied with ink during use of the pen inwriting.

Another object is the provision of an improved construction for thepiston of a fountain pen of the sort specied W ch will render thefilling of the pen more certain.

Other and further objects of the invention will be pointed out orindicated hereinafter or will be apparent from the following descriptionof the invention, or upon use of pens embodying it.

For the purpose of aiding in an explanation of the invention, I show inthe accompanying drawing forming a part of this specification, andhereinafter describe, certain structural forms in which the inventionmay be embodied. It is to be understood, however, that these arepresented merely for purpose of illustration, and that they are not tobe interpreted in any fashion calculated to limit the appended claimsshort of the true and most comprehensive scope of the invention in theart.

In said drawing,

Fig. 1 represents a shortened longitudinal section of a fountain penembodying the invention;

Fig. 2 is a part longitudinal section of the same construction butshowing certain of the parts in other positions;

Fig. 3 is a transverse section on approximately line 3 3 of Fig. 1;

Fig. 4 is a longitudinal sectional detail showing a somewhat modifiedform of construction;

Fig. 5 is a transverse section on substantially line 5 5 of Fig. 4;

Fig. 6 is a part longitudinal section showing a second modifiedconstruction;

Fig. 7 is a transverse section on substantially line 'l-- of Fig. 6; and

Fig. 8 is a part longitudinal section like Fig. 2, but showing therelationship of parts during downward movement of the piston.

This invention relates primarily to that type of self-filling fountainpens wherein the pen barrel affords a cylindrical ink reservoir in whicha piston is operable to induce a negative pressure behind the piston onits downward stroke, the evacuated portion of the barrel being placed incommunication with the rpen section when the piston, at the end of itsdownward or inward stroke, reaches a clearance space at the lower end ofthe barrel, thereby permitting induction of ink through the ink-feedingpassages of the pen 5 section and into the reservoir above the piston.Pens of this type heretofore employed have shown a tendency to starvethe pen point in the course of continuous and rapid writing, due toinsuciently free feed of ink from the reser- 10 voir past the piston.This has been found to occur even when the clearance space extends aboutthe entire periphery of the piston. It is one of the objects of thepresent invention to obviate this diiiiculty without involving anyincrease in the external diameter of the pen barrel at this point, andwithout weakening the barrel in this locality. The manner in which theseand Various other objects and advantages of the present invention areobtained, as well as the nature and character of the invention, will beascertained most readily by a detailed consideration of the illustrativeembodiments shown in the accompanying drawing, which embodiments, willnow be described. The pen includes a barrel I0 which affords a bore orinternal cavity lila of uniform cross-sectional size and contoury whichcavity constitutes an ink reservoir. At its lower terminus it mergesinto a cavity Illb of greater cross-sectional size such as to aiTord aclearance space for the piston as hereinafter described.

In the upper end of the barrel is xed a bushing II which supports awasher I2, and also in the upper end of the barrel is secured a sleeve I4 35 having a cavity which houses a plurality of layers I5 of packingmaterial, all or some of which may be exible and compressible. Thispacking is compressed against the washer I2 by the screwing down of thesleeve I4. The bushing Ii, plate I2, sleeve I4 and packing material I5are provided with axial apertures which align to aiord a passage for thepiston rod I6.

The piston rod, as seen more particularly in Fig. 2, comprises a core Iaof metal wire and a sheath I6b of hard rubber vulcanized thereon. Theupper end portion of the core extends beyond the sheath and has a jarnbnut Il and a stepped nut I8 threaded thereon. A short distance from itslower end the sheath is formed with a peripherally projecting shoulderIBc. Fitted on the lower end portion of the sheath is a rigid collar I9,of hard rubber, which is counterbored to accommodate and abut theshoulder |60. Centered on the sheath below this 5 Vbar has theconventional ink collar I9 is a disk 20 of flexible rubber, said diskbeing of substantially greater diameter than the diameter of the barrelbore Ia and of somewhat lesser diameter than the diameter of the cavityIb. The lower end of the core I6a projects beyond the lower end of thesheath and has screwthreaded thereon a hard rubber spider nut 2l, theupper face of which is frusto-conical in form and provided with aplurality of longitudinally extending slots 2Ia. Nut 2l is set uptightly against the lower end of the sheath I6b below disk 20.

The flexible disk 20 is provided with a plurality of apertures 20atherethrough, same being arranged so as to overli-e the slots 2 la ofnut 2|, and nut 2l and collar I9 are of approximately the same maximumdiameter, which is substantially less than that of the barrel boreIlla.. Collar I9, disk 20 and nut 2| constitute the piston. Theproportions of the parts are such that when the piston is drawn upwardlyinto bore Illa, the marginal portion of disk 20 will rub against thebore wall, with the result that the disk will be flex-ed downwardlyagainst the upper conical surface of nut 2I, by which the disk will hesupported in such position that its marginal portion will be held incontact with the bore wall. With the disk in this position, fluid maynow freely from the portion of the bore lila above the disk 2li throughthe apertures or ports 20a and the slots 2Ia.. During such upwardmovement of the piston, the disk 20 and nut 2l, by virture of thebearing of the former upon lthe bore wall, form a centering guide forthe lower end of the piston rod, guiding it in axial alignment with theaperture of the packing gland in which the piston rod slides.

Duringl the downward or inward stroke of the piston the flexible disk 20is support-ed by the collar I9 in a position such that its outer portionis held in sealing contact with the bore wall, and in which position theports 20a are closed against the lower face of the collar I9. Thisprevents passage of air into the bore above the piston during the timethe latter is moving downwardly in said bore. As a result, ay partialvacuum is created in the bore above the piston. As the piston passesinto the cavity lub, this vacuum is broken when the marginal portion ofthe disk passes the upper `end of the cavity.

The lower end of the barrel is fitted with a suitable pen section, asshown in Fig. l, including a feed bar 2li and pen point 25. The ink feedfeed channel 24a for feeding ink to the pen point, and. which alsoserves as a channel for admission of ink into the barrel in the filling'operation.

In the construction illustrated in Figs. 1, 2 and 3, the sleeve 22 isprovided adjacent its upper end with a transversely extending pin 2B, toact as a deiiector for the piston. This delector is arranged in suchposition that as the piston reaches the end of the downward or inwardstroke, the beveled lower end of nut 2I will engage the deilector, andcam the lower end of the piston rod and the piston laterally, as to theposition illustrated in Fig. 1. This movement is accommodated by aslight flexing of the piston rod. This lateral displacement of thepiston increases the clearance between the margin of the disk 23 and thewall of the cavity IDD at one side of the piston. In the embodimentshown in Fig. l this increase of clearance occurs at the side of thepiston corresponding to the under side of the feed bar and pen point,lbut it is obvious that the displacement oi the piston in any otherradial direction relative to the feed bar may be likewise effected.

By virtue of this increased clearance between the margin of disk 20 andthe wall of cavity Ib a liberal passage is provided for flo-w of inkfrom the ink reservoir to the pen section and the ink feed channel 24aof the feed bar and for passage of air bubbles in the oppositedirection. Writing ink has more or less viscosity which causes it tobridgenar-row spaces under capillary attraction and interfere with theflow of the ink through such spaces. By virtue of the lateraldisplacement of the disk 20 as above described, the clearance betweenthe margin of the disk 20 and the wall of cavity lob is increase-d tothe point that the ink cannot lm across it and prevent ingress of thesmall air bubbles from the pen section to the ink reservoir.

As a consequence, when the pen is used in writing, an adequate supply ofink to the feed bar is maintained at all times, so long as there is inkin the reservoir.

The lateral displacement of the piston is illustrated in Fig. 3, inwhich the wall of the cavity lob is defined by the dotted line somarked, and the periphery of the disk 20 is defined by the dotted circlemarked 2li. It will be noted that there is no distortion of the disk 2owhen it is inthe laterally displaced position. Hence it is in no waydisabled for the necessaryclose cooperation with the bore wall in anensuing lling operation.

In the modified construction illustrated in Figs. 6 and 7, thed-electing member 28' is formed as a lug;l on the pen section sleeve,and 'cooperates with the nut ZI to displace the piston laterally asabove described.

In the further modified construction illustrated in Figs. 4 and 5, thedeiiecting member 28 is formed as a lateral extension of nut 2|, andcooperates with the upper portion of the pen section sleeve to effectthe lateral displacement of the piston.

The piston rod is equipped at its upper end with a small capi 3i) havingan external form and iinish appropriate for the barrel, said cap beingmolded onto, or otherwise affixed to, the nut I8. The lower threadedportion of this nut is adapted to screw into the threaded female portionat the upper end of the sleeve I4. The nut I8 is xedly secured to thepiston rod. A suitable finish ferrule 3l is mounted on the upper end ofthe sleeve I4 to provide a seat for the skirt portion of the cap 30 andan appropriate finish for the joint between the cap and the upper end ofthe barrel.

An appropriate pen cap 32 is provided for housing the lower portion ofthe pen section when the pen is not in use.

In o-peration of the device to accomplish the filling of the pen, thepen cap 32 having been removed, the cap 30 is rotated to unscrew the nutI8 from the sleeve I4. The piston is then drawn upwardly in the barrelby traction on the cap 30. Incident to this operation, the disk 2D isflexed downwardly as seen in Fig. 2, and the ports Ella opened, so thatink and air in the bore lila. find free outlet therethrough, themarginal portion of the disk` being held in contact with the bore wallby the flange of nut 2l. After the piston has been thus drawn upwardlyto the limit of its upward or outward stroke, it is pushed downwardly inthe barrel by pressure on the cap 30. At the start of this downwardAmovement of the piston, the disk 20 is iiexed into engagement with thecollar I9, so that the ports 20a are closed and the marginal portion ofthe disk is maintained firmly in contact with the bore wall, asillustrated in Fig. 8, during the downward movement of the piston in thebore I ila. Before the piston reaches the lower end of the bore lila,the protruding portions of the pen point and feed bar and the lowerextremity of the pen section sleeve 22 are immersed in a body of ink.Downward movement of the piston then being continued, disk 2@ enterscavity Ib and deflector 28 engages nut 2i and causes the piston to bedisplaced laterally. The bore cavity Ito. being thus placed incommunication with the pen section, ink will be forced into thereservoir through ink channel 24a and past disk 2B. 'Ihen nut I8 isscrewed home in sleeve I4, thus securing the piston in the positionshown in Fig. 1.

The subjects matter of the pen section construction and the piston andpiston rod construction illustrated and described but not claimed hereinare claimed in my copending applications Serial Nos. 749,152 filedOctober 20, 1934, and 119,718, January 9, 1937.

What I claim is:

l. In a foimtain pen, in combination, a barrel having a boreconstituting an ink reservoir and a cavity of greater diameter than thebore at the lower end thereof, a piston device for cooperation with thewall of the bore, a piston rod opierable to move said piston devicelongitudinally in the bore and into said cavity, and means in the barrelfor cooperation with said piston rod to hold the piston device in alaterally displaced position in said cavity.

2. In a fountain pen, in combination, a barrel having a boreconstituting an ink reservoir and a cavity having a portion of greaterdiameter than the bore at the lower end there-of, a piston device, apiston rod operable to move the piston device longitudinally in rubbingengagement with the wall of the bore and to positions within thelongitudinal span of the cavity, and means adapted to cooperate with thepiston rod for displacing the piston device laterally relative to a wallof the cavity incident to longitudinal movement of the piston device inthe cavity.

3. In a fountain pen, in combination, a barrel having a boreconstituting an ink reservoir,v a piston device movable longitudinallyin the bore and adapted for fluid-tight cooperation with the wallthereof, said barrel having a cavity at the lower end of the bore toprovide a passage for ow of ink past the piston, and means in the barrelbelow the piston device for cooperation with the piston rod to eiTectlateral displacement of the piston relative to said passage to increasethe clearance between a wall thereof and the periphery of the piston.

4. In a fountain pen, in combination, a barrel having a bore forreceiving ink, a piston movable longitudinally in rubbing contact withthe bore wall, said barrel having an ink passage leading' from the lowerend of the bore, a piston rod operable to move the piston longitudinallyof the bore, and a deflector at the lower end of the barrel for holdingthe lower end of the piston rod in a laterally displaced positionrelative to said passage.

5. In a fountain pen, in combination, a barrel having a bore forreceiving ink, a flexible piston movable longitudinally in rubbingcontact with the bore wall, said barrel having an ink passage for flowof ink from the bore past the piston, and means in the barrel adaptedfor cooperation with the piston rod to increase the clearance between aportion of said passage and the piston.

6. In a fountain pen, in combination, a barrel having a bore forreceiving ink, a piston rod movable longitudinally therein, a guide andpacking for the piston rod mounted at the upper end of the barrel, apiston carried on the rod adjacent its lower end and adapted for sealingcooperation with the bore wall, the barrel aifording i an enlargedcavity at the lower end of the bore into which cavity the piston may bemoved, and means in the barrel for cooperation with the piston rod todeflect its lower end laterally when the piston is in said cavity.

7. In a fountain pen, in combination, a barrel having a bore adapted toreceive ink and a cavity at the lower end of the bore, a piston rodslidably mounted in the upper end of the barrel for movementlongitudinally in the bore, a pen section sleeve mounted in the lowerend of the barrel, a piston mounted on the piston rod adjacent its lowerend and adapted for rubbing cooperation with the wall of the bore, and adelecting device mounted in the pen section sleeve for cooperation withthe piston rod to displace its lower end and the piston laterally insaid cavity.

8. In a fountain pen, in combination, a barrel having a bore adapted toreceive ink and a cavity at the lower end of the bore, a piston rodslidably mounted in the upper end of the barrel, a piston mounted on thepiston rod adjacent its lower end and adapted for rubbing cooperationwith the wall of the bore, a retaining member mounted on the lower endof the rod for holding the piston thereon, and means disposed in thelower end of the barrel for engagement with said retaining member tohold the piston in laterally displaced position in said cavity.

ALBERT H. STENERSEN.

